serial: mxs-auart: put the device in the error path

The mxs_auart_probe() gets the device by the get_device().
So we should put the device in the error path to balance the
device's reference counter.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/mxs-auart.c

@@ -781,6 +781,7 @@ out_free_irq:
 	auart_port[pdev->id] = NULL;
 	free_irq(s->irq, s);
 out_free_clk:
+	put_device(s->dev);
 	clk_put(s->clk);
 out_free:
 	kfree(s);